Art of making metal tubing



2 Sheets-Sheet 2 lNVENTOR Feb. 92

\ V F. MAGIDSON ARTIQF MAKING METAL TUBING Original Filed Oct. 2'7; 1920 v v Q\ Patented Feb. 3, 1925.

UNITED s'r-A'rss PATENT OFFICE.

FRANK MAGIDSON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T PROGRESS TUB COMPANY, A CORPORATION OF PENNSYLVANIA. i 4

ART OF MAKING METAL TUBING.

Application filed October 27, 1920, Serial No. 419,846. Renewed June 16, 1924.

To all whom it may concern:

Be it known that I, FRANK MAGIDSON, a. citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of'Pennsylvania, have made a new and useful Improvement in-the Art of Making Metal Tubing, of which the following is a specification. v

This invention relate to the art of making metal tubing and more especially to the art of making butted orbutt-weld tubing from skelp or strip metal in a cold state.

An object of this invention is to provide a method for making butted or butt-Weld tubing or other hollow sections of any desired shape or cross section from strip metal while in a cold state. v

A further object is to provide a method whereby metal tubing of relatively light ga e may be made at small cost.

still further object is to provide a method whereby stripmetal in a single pass or operation may be converted into butted tubing of any desired cross section.

These as well as other objects which will appear to those skilled in the metal tubing art, I attain by the method described in the specification and diagrammatically illustrated in the drawings forming part of this specification. I

The method broadly consists in laterally or transversely bending a continuously propelled'metal strip simultaneously in opposite directions, in carrying on this lateral. bending progressively 1n increments and si.

multaneously with such progressive lateral bending, in swedging the bent portion by subjecting it to periodically applied transverse pressures whereby the lateral bending of the strip is facilitated and the metal set to finished tubular form.

In carrying out this method of forming tubing or other hollow articles from strip metal, the strip from which the tubing is to be formed is continuously propelled 1ongitudinally by means of fiat feed rolls. The

strip within the rolls and in its passage from the rolls to the forming dies, is guided above and below and prevented from bending in either a lateral or longitudinal direction. .The strip is forced into and through a sectional die having whenclosed a through passage of the same cross section as the finished tubing which it is desired to v produce.

In order that the strip may be progressively bent laterally in increments-the forward or entering face of the die is out in a plane diagonally disposed to the major aris of the die passage, in other words, diagonally to the line of movement of the strip, and a mandrel of the same cross section as the desired interior crosssection of the tube is supported at the entrance of the die and projects rearwardly into the through passage. v 1

The cutting away of the entrance face of the die diagonally to the line of travel of the strip presents a channel beneath the mandrel which. increases in depth as it approaches the rear portion of the die, or, in other words, the walls of the die channel increase in height from the forward end of the die to that point at which the walls meet to form the closed die passage. By means of these walls of progressively increasing height, the metal strip as it is forced through the-die is simultaneously bent laterally in opposite directions from the median line of the strip in increments until the opposite edges of the strip arrive in pro-ximity one to the other.

If the tubing or other hollow article to be formed is of symmetrical contour, then the strip will preferably be bent laterally equally on opposite sides of its median line, so that the median line of the strip, the major axis of the tube, and the tube seam will lie in one and the same plane.

In order tofacilitate the lateral bending of the strip, to swedge the material to form and to set it after it reaches finished form, the die is longitudinally split into two S60. tions and these sections are mounted so as to be capable of being separated by the strip as it is forced thereinto and the swedging action to which the work, that is the bending strip and the bent strip surrounding the mandrel, is subjected is accomplished by periodically bringing the die sections together. I findthat the swedging is facilitated by causing the die to close at frequent periods. Satisfactory results have been accomplished by closing. the die 750 times during feet of lon itudinal movement of the p i strip, therethroug and I have found that it is desirable to use a die of from two to three inches in length, that is, one having a through passage of from two to three inches, so that every portion of the strip is subjected to a number of swedging actions thereb insuring a setting of the metal into finishe form.

In the drawings, Figure l diagrammatically illustrates one form of mechanism for practicing this method. In this view, 10 represents a flat strip of metal of the desired width; 11 and 12 represent flat cylindrical feed rolls which may both be positively driven from an suitable power source, such as an electric motor and at the desired speed; 13 and 14 represent guides which guide the strip tangentially as it leaves the feed rolls. These guides are relatively narrower than the metal strip as shown in Fig. 2, and extend into narrow grooves turned in the feed rolls as shown at 15 and 16 in Figsil and 2. The die is represented at 1'. and comprises two sections as shown at 18 and 19 in Fig. 3. The front faces 20 and 21 of the composite die lie in the same plane, and this is disposed diagonally -to the line-of travel of the strip. By thus beveling the entrance face of the composite die, an entrance opening 22 is'formed having Walls of progressively increasing height from the forward end 23 to the point 24 at, which the through passage of the die is completely closed.

The mandrel about which the strip is bent is represented at 25 and this mandrel is supported at 26 and has a cylindrical projection 27 (where round tubing is to be made) which extends into the die passage. Fig. 4 illustrates the progressively lateral bending of the strip simultaneously in 0 osite directions from'its median line. 11 ig. 5, I have illustrated the means for periodically closing the die around the mandrel whereby the tubing is swedged to finished form. I

In this swedging mechanism, each die section is bolted to a movablv mounted support. Thesesupports are numbered 28 and 29 respectively. The supports are guided so as to reciprocate at right angles to the line of movement of the strip and the die sections are periodically brought together by means of the links 30, levers 31 and operating camwheel 32 which may be driven from any suit-able power source such as an electric motor and at the desired speed with relation to the strip movement.

In Figs. 6, 7, 8 and 9, I have illustrated tubing of various cross sections which may be made from strip material in a cold state by means of this method. These views also illustrate the dies and mandrels in cross section. Fig. 10, 11 and '12, when taken in conjunction with Fig. 6, diagrammatically illustrate the progressive lateral bending transverse I sists in progressively bendin of the strip to round tube form; the progressive lateral bending of the strip to the forms of tubing shown in Figs. 7, 8 and 9 will be apparent to those skilled in this art from Figs. 10, 11 and 12.

If it is desired to weld the seam, any of the well-known welding methods may be employed and the welding can be continuously carried out as the strip issues from the guide and support device 33.

The welding may be either done by means of any oxyacetylene flame ,or electric welding may be employed. I

If the strip materialto be converted into tubing is of relativel short lengths, the strip entering the fee roll can be utilized .for forcing the latter end of the preceding strip through the die. No matter how long or short the strips ofmaterial are, they may be butt-welded one to the other prior to insertion between the feed rolls and thus tubing of any desired length may be made from strips of. different lengths.

' Having thus described my invention, what I claim is 1. The art of forming hollow sections which consists'in bending a strip of metal transversely on opposite'sides of its median line around a mandrel while moving longitudinally and in subjecting the portion of the strip so bent to periodically applied transverse pressure whereby it is swedge finished.

2. The art of making tubing which consists in bending a longitudinally moving strip of metal transversely equally on opposite sides of its median line around a mandrel and in subjecting the bent por tion of the strip while moving longitudinally to periodically applied transverse pressure, whereby it is swedge finished.

3. The art of forming tubing which consists in progressively bending a longitudi-- nally moving strip of metal transversely and equally on opposite sides of its median line around a mandrel and in subjecting that portion, of the strip around wthe mandrel and while moving to periodically applied pressure, whereby it is swedge finished.

4. The art of forming butted tubing which consists in progressive y bending a longitudinally moving strip of metal transversely on opposite sides of its median line around a mandrel, in subjecting that portion of the strip around the mandrel to periodically a J plied transverse pressure and then in un1ting the edges of the strip to form a buttweld.

5. The art of forming tubing which cona longitudinally moving strip of metal transversely in opposite directions around a mandrel, in subjecting that portion of the strip around the mandrel to periodically applied transverse pressure, whereby it is swedged and then in butt-welding the swedged tubing.

6. The art of forming tubing which consists in forcing strip metal through a die capable of expansion due to pressure exerted by the strip and in periodically opening and closing said die to swedge the strip to tube form during the movement of the strip through the die.

7. The art of forming tubing which consists in feeding fiat metal strip through a die capable of expanding at right angles to the median line of the strip and in periodically opening and closing said die to swedge said strip to tube form during the movement of the strip through the die.

8. The art of making metal tubing which consists in continuously moving a strip of metal longitudinally and while so moving, in subjecting it to periodic swedging of equal value applied thereto simultaneously on opposite sides of the tube sea-m.

9. The method of forming tubing whichconsists in incrementally bending a moving strip in opposite transverse -d1rect1ons around a mandrel during the movement thereof past the mandrel and in swedging the bent portion of the strip while forwardly moving.

10. The-method of forming tubing which consists in simultaneously bending a forwardly moving metal strip transversely in opposite directions around a mandrel, in increasing the degree of such transverse bending as the strip progresses longitudinally and in swedging the bent portion thereof into tubular form by subjecting it to periodic transverse pressure.

11. The art of making metal tubing which consists in moving a strip of metal. past a mandrel and during such movement in bending the strip on opposite sides of its median line around the mandrel in increasing amounts as the strip rogresses and in simultaneously swedging t e strip into tubular form.

12; The art of forming hollow sections which consists in continuously moving a strip of metal through a sectional die whereby the die sections are forced a art by the moving strip, in closing the ie sections whereby periodic swedging is 1 carried on during the movement of the strip through the die.

13. The art of formin tubing which consists in forcing a meta blank through a longitudinally s lit die whereby the die sections are cause to separate during movement of the strip and in periodically closing the die to swedge the blank to finished form.

'14. The art of makin metal tubing which consists in continuous y moving a metal strip len thwise between dies located on opposite si es of a mandrel, in opening said dies by pressure of the moving strip and in periodically closing. said dies whereby the strip is swedged to finished form.

15. The method which consists in periodically forcing the sections of a split die toward amandrel and in feedin strip material through said die past said mandrel during the opening and closing movements.

of said die whereby said material is forced into tube form around said mandrel.

In testimony whereof, I have hereunto .subscribed my name this th day of October, 1920.

FRANK MAGIDSON. 

